The present invention relates to a method and machine for the making of composite filter mouthpieces for cigarettes, cigars or cigarillos. More particularly, the invention relates to improvements in a method and machine for the manufacture of composite filter mouthpieces wherein a tubular envelope contains different types of filter material. Still more particularly, the invention relates to improvements in a method and machine for the production of filter mouthpieces wherein a tubular envelope contains one or more cylindrical plugs or wads and one or more disk-shaped elements of gas-permeable filter material and wherein the material of the filter plug or plugs is normally different from the material of the filter disk or disks.
The invention also relates to a method and machine for the making of rod-shaped smokers' products which embody the improved filter mouthpieces.
It is already known to provide cigarettes, cigars and/or cigarillos with composite filter mouthpieces which contain two or more different filter materials. It was found that a composite mouthpiece is often a more effective means for segregating from tobacco smoke substantial quantities of nicotine, tar and/or other deleterious ingredients. For example, it is known to employ filter mouthpieces wherein a tube contains a wad or plug of acetate fibers and a charge of granular filter material, e.g., activated carbon. It is also known to replace the charges of granular or powdery material with thin disk-shaped filters which consist of glass fibers alone or glass fibers impregnated with one or more chemicals. The relatively thin glass fiber disks are surprisingly effective as concerns their ability to absorb various harmful ingredients of tobacco smoke. However, such filter elements exhibit the serious drawback that they are much more difficult to assemble with other components, especially when the filter mouthpieces are to be produced at the rate of several thousand per minute. The problems in connection with the manipulation of relatively thin disk-shaped filters are attributed mainly to the small axial length of such filter elements as well as to the fact that they are readily deformable. As a rule, the material of filter disks is quite soft so that they are likely to be deformed to an extent which renders them useless in composite filter mouthpieces for cigarettes or the like. The problems in connection with the manipulation of filter disks are equally severe when the filter mouthpieces are to be assembled in the form of continuous filter rods which are thereupon subdivided into filter mouthpieces of desired length, when the components of filter mouthpieces are inserted into tubular envelopes which travel sideways, as well as when the filter mouthpieces are assembled and immediately attached to rod sections which constitute plain cigarettes, cigars or cigarillos.